Modules

Modules are a way to encapsulate methods, classes, and constants into a single, separate namespace. Modules provide two main benefits: they act as containers for reusable code, and they enable a form of multiple inheritance through a mechanism called "mixins."

module Greetings
  def say_hello
    puts "Hello!"
  end

  def say_goodbye
    puts "Goodbye!"
  end
end

class Person
  include Greetings  # Include the Greetings module to use its methods

  attr_accessor :name

  def initialize(name)
    @name = name
  end
end

# Create an instance of the Person class
person = Person.new("John")

# Use methods from the Greetings module
person.say_hello # => Hello!
person.say_goodbye # => Goodbye!

The Person class includes the Greetings module as a minxin using the include keyword.

Modules are often used to share functionality between classes without using traditional inheritance. They allow you to group related methods together and include them in multiple classes.

Code Challenge

Create a module called ShapeMixin that provides methods for calculating the area and perimeter of different shapes. Include this module in two different classes Rectangle and Circle to enforce the required methods on them.